I rode the Flows for 7 hours yesterday, here's my experience. I had adjusted them at home and spent quite a bit of time getting them just right. That was worthwhile as I only had to add a click or 2 more on a couple buckles. I had very little trouble getting into the Flows standing up, felt like I wrestled with the a bit more early on, and got much smoother after an hour or two.
Performance wise I felt like these were kinda vague feeling compared to the 2010 Ride EX's I ran last week. That feeling of vagueness wore off after a couple hours, they just feel different than strap-ins IMO. I suspect there is a little feedback you give up to run Flows, and even at my beginer level I could feel it. However, as the night progressed I got used to the feel and I don't think they were holding me back at all.
The comfort on these are superb, many Flow reviews talk about how the pressure is distributed accross the large top-strap, which IMO is very true. Absolutely no pressure points and I was boarding for 7 hours.
So at the end of the day, these bingings accomplished what I expected them to. Get in and out of them easily w/o having to sit down, all day comfort (more so than straps in my experience), and don't cost me much (if any) performance. If maximum performance was my main concern, I would likely look to some kind of strap binding, but for what I've got going on, I like these.